Heating unit



C. C. ABBOTT.

HEATING UNIT.

APPLICATION FILED MAY 5, 1919.

Patented Oct. 17-, 1922.

Inventor" Charles C.Abbott, by \fi f r/r His Attorneg.

Patented Oct. 17, 1922. l

UNITED STATES CHARLES C.

1,432,434 PATENT OFFICE.

ABBOTT, OF PITTSFIELD, MASSACHUSETTS, ALSSIG'NOR 'IO GENERAL ELECTRIC COMPANY, A CORPORATION 01 NEW YORK.

. HEATING UNiIT.

Application filed-May 5, 1819. Serial No. 294,837.

To all whom it may co 21cm.-

Be it known that I, CHARLES C. ABBOTT, a citizen of the United States, residing at Pittsfield, county of Berkshire, State of Massachusetts, have invented certain new and useful Improvements in Heating Units, of which the following is a specification.

My invention relates to electric heating units and more especially to heating units of the type in which a resistance conductor is wound upon a core of insulating mate- ,rial and which may be inclosed in a metallic sheath and insulated from it by a thin dense layer of insulating material, and has for its. object the improvement in a device of this character. i

This unit is well'adapted for use with machines subject to considerable vibration, such as shoe making machines. The main difliculty heretofore has been to get a heating unit that could withstand the vibrations, since the core which is the heaviest element in the unit,.on becoming slightly loose. may pound itself against the insulated sides inclosing the core, and short-circuit the resistance conductor on the metallic sheath. One of the objects of my invention is to provide a heating unit that will overcome this difliculty. Another object of my invention is'to provide a simple, eflicient and economical terminal connection. Further objectsv and purposes of my invention will appear in the courseof the following specification in which I have shown my invention embodied in concrete form for the purpose of illustration.

My. invention will best be. understood by reference to the accompanying drawings in which'Fig. 1, is a longitudinal section, partly in elevation, of one form of heating umt embodying my invention. Fig. 2 is an end view thereof and Fig. 3 is a detail sectional view thereof showing the manner in which the heating element is secured to the ter-' minals.

Referring to the drawings, 1 is a core of insulating material, preferably of lava, in

which two holes, 2 and 3, have been drilled lengthwise to accommodate the terminals 4 and '5 respectively. The hole 2 extends part way into the core, whereas the hole 3 extends clear through the core as shown. Two'holes 6 and 7 are drilled radiall into the core, one being at each end thereo connecting with the holes 2 and 3 respectively and extending beyond the latter holes as shown at 8 and 9 in Fig. 1. Each of the terminals 4 and 5 is provided with a hole 10 and 11 respectively extending through said terminals and a groove 12 and 13 respectively around the terminals near each of the holes 10 and 11. It will be observed that the holes 10 and 11 through the terminals and the grooves, thereon coincide with the hole's 6 and 7 of the core, respectively, as shown in Fig. 1. A resistance conductor 14 is wound about the core 1, and secured at its ends to the terminals 4 and 5 respectively in the manner'hereinafter described. A metal sheath 15 screw threaded on its inside at each end incloses the core 1, with. an intervening layer of refractory insulating powder 16, such as magnesia insulating the resistance conductor from the sheath. The sheath is closed at one end by insulating washers, preferably mica washers 17, which are provided with holes. 18 and 19,

through which the terminals 4 and 5 project respectively, which washers are held in place by a ring 20, screw threaded on its outside to engage the threads of the sheath. At its opposite end the sheath is closed by a disc or member 21 which is screwed Into the sheath. I

In the manufacture of a heatin unit in accordance with my invention, ho es 2 and 3 are drilled lengthwise in the core 1, and the terminals 4 and5 are inserted in the holes 2 and 3 respectively so that the holes and grooves :of said terminals coincide with the radial holes 6- and7 respectively. One end of the resistance conductor 14 is then inserted in holes 6, through hole 10 of the terminal 4, to the bottom of hole 6 at 8.

allows suflicient space between the conductor for insulation. The conductor is then out leaving suificient to form an end which is inserted in hole 7 'of the core andhole 11- of terminal 5, whereupon the terminal is twisted causing the end to tighten in similar manner as above described in the case of terminal 4. In this case however, such twisting also takes -up any slack of the wire on the core. Mica washers 17 are now placed at the head of the core 1, the terminals projecting through the holes 18 and 19 therein. The threaded ring 20 is then placed over the washers, llhe unit thus formed is surrounded by the metallic sheath 14: which is slipped over the unit from the end opposite the terminal projection and screwed to the ring 20. filling cup is then secured to the opposite end of the sheath which holds the core central while it is being filled with a refractory insulating powder by means of a vibrator machine. After the sheath is so filled, the filling means are removed and the member 21 is screwed into place. The

'sheath is then compressed, preferably by swaging, which compresses the insulating material to a hard dense mass and fixes the turns of the resistance conductor to avoid any change in the relation of its parts due to the vibration of the machine on which it is used.

While I have described my invention as embodied in concrete form and as operating in a specific manner in accordance with the provisions of the patent statutes, it should be understood that I do not limit my invention thereto, since various modifications thereof will suggest themselves to those skilled in the art without'departing from the spirit of my invention, the scope of which is set forth in the annexed claims.

What ll claim as new and desire to secure by Letters Patent of'the United States, is:

1. An electric heating unit comprising a cylindrical core of insulating material, a metallic terminal inserted longitudinally thereof, and a resistance conductor wound on said core and having one end locked between the terminal and the core at a point within the core.

2. An electric heating unit comprising a cylindrical core of insulating material, a metallic terminal inserted longitudinally thereof, and a resistance conductor wound on said core and having one end wound on the terminal within the core so as to be held between the terminal and-the core.

3. An electric" heating unit comprising a cylindrical core -of insulating material, metall ic terminals inserted longitudinally thereof, and a resistance conductor wound on said core and having its-ends wound on the terminals, respectively, within the core so as to be wedged between the terminals and the core.

t. electric heating unit comprising a cylindrical core ofinsulating material, me-

tallic terminals inserted longitudinally thereof and having openings therethrough conductorand core, and powdered heat refractory insulating material compacted to A a hard dense mass within said sheath.

6. An electric heating unit comprising in solid cylindrical support of insulating material, a metallic terminal inserted longitudinally thereof, a resistance conductor wound onsaid support and connected to the terminal, a metallic sheath surrounding the resistance conductor and support, and powdered heat refractory insulating material compacted to a hard dense mass within said sheath. v

7. An electric heating unit comprising a solid cylindrical support of insulating ma-' terial having longitudinal holes therein, metallic terminals inserted insaid holes, a resistance conductor wound on said support and connected to the terminals, a metallic sheathsurrounding the resistance conductor and support, and powdered heat refractory insulating material compacted to a hard dense mass within said sheath.

8. An electric heating unit comprising a cylindrical core of insulatin material, a metallic terminal inserted lb thereof, a resistance conductor wound 0.1 said core and havingone end wound on the terminal within the core so as to be held between the terminal and the core, and a metallic sheath surrounding the resistance conductor and spaced therefrom by compacted powdered insulating material.

9. An electric heatin unit comprising a cylindrical core of ins ating material havngitudinally 10. An electric heating unit comprising a cylindrical core of insulating materialhaving longitudinal holes therein and transverse ho es opening into the same, terminals inserted in said longitudinal holes having holes .therethrough coinciding with the transverse holes in the core, a resistance conductor wound on said core and secured to the terminals through the holes therein by turning the terminals and a metal sheath surrounding the resistance conductor and in good thermal relatlon therewith.

11. An electric heating unit comprising a cylindrical core of insulating material havinglon itudinal holes therein and transverse ho es opening into the same, terminals inserted in said longitudinal holes having holes therethrough coinciding with the transverse holes in the core, and a resistance conductor wound on said core and havin its ends passing through the holes in the terminals and wound on the terminals so as to be secured between the terminals and the core.

12. A heating unit comprising a cylindrical core of insulating materlal having longitudinal holes drilled therein and transverse holes opening into the same, terminals inserted in said longitudinal holes having holes therein, and grooves adjacent thereto said holes and grooves coinciding with the transverse holes in the core, a resistancev conductor wound on said core and secured to the terminals through holes therein and around said grooves against the core, and a metal sheath surrounding the resistance conductor and in good thermal relation therewith.

13. The method of making an electric heating unit which consists in inserting a metallic terminal longitudinally of a cylindrical insulating core, connecting a resistance conductor to the terminal at a point within the core, winding the resistance conductor upon the core and then tightening the resistance conductor by turning the terminal.

14. The method of making an electric heating unit which consists in inserting two metallic terminals longitudinally of a cylindrical insulating core, connecting a resistance conductor to one terminal at a point longitudinally of a cylindrical insulating core having a hole coinciding with the hole in the terminal, passing a resistance conductor through the holes in the .core and terminal, winding a resistance conductor upon the core and then tightening the resistance conductor by turning the terminal. In witness whereof, I have hereunto set my hand this second day of May, 1919.

CHARLES C ABBOTT. 

